1. Field of the Invention
The present invention relates to a transmission device, and more particularly to transmission device for a tube bending machine. The transmission device has a first power means and a second power means to drive the moving device to move along the guiding track, wherein the motor of the second power means is controlled by a clutch so that a boost is provided to the moving device and thus a tube is able to be successfully bent.
2. Description of Related Art
A tube bending machine is specially used in the work of tube bending processes. When the workpiece (the tube) is being bent, the outer periphery of the workpiece is being stretched and the inner periphery of the workpiece is being compressed. In order to prevent the workpiece from being torn apart during the bending process, usually a fast conveying speed and large boost are provided by the tube bending machine.
U.S. Pat. No. 5,426,965 “Carriage Boost Drive” discloses, with reference to FIGS. 8 and 9 of this present application, a tube bending device (41) having a tube bending module (411) on top of a base (40) and a clamping module (42) on the side of the tube bending module (411). A transmission device (50) is mounted on the base (40) opposite to the tube bending device (41) and has a sliding seat (52) slidable along a sliding track (51) on top of the base (40) and an auxiliary booster (53) on the distal end of the sliding seat (52). The sliding seat (52) has a mounting element (521) extending through the sliding seat (52) for mounting the tube (60) thereon and the auxiliary booster (53) has a cylinder (531) with a connector (532) to connect to the mounting element (521). A locking device (54) is mounted at the distal end of the auxiliary booster (53) to control the cylinder (531).
When the conventional tube bending machine is employed, the mounting element (521) clamps one end of the tube (60), the other end of which is facing the tube bending module (411). Then the motor of the sliding seat (52) drives the booster (53) and the locking device (54) to move toward the tube bending module (411) along the sliding track (51). After the predetermined portion of the tube (60) is aligned with the tube bending module (411), the sliding seat (52) is controlled to stop movement and the cylinder (531) of the auxiliary booster (53) is locked by the locking device (54). Thereafter, the oil pressure from the cylinder (531) drives the tube (60) to move toward the tube bending module (411) via the connector (532) and the mounting element (521). Thus the tube (60) is able to be bent according to the predetermined shape. After the tube (60) is bent, the tube bending device (41) and the clamping device (42) leave the tube (60) and the mounting element (521) releases the tube (60). The cylinder (531) is controlled to move rearward to pull back the mounting element (521). Then the locking device (54) is unlocked and the motor of the sliding seat (52) drives the sliding seat (52) and the auxiliary booster (53) back to their original positions.
Although the conventional tube bending machine is able to provide a fast drive to the tube when the tube is transported to the tube bending device and a slow bending process, the tube bending process is limited due to the length of the cylinder.
To overcome the shortcomings, the present invention tends to provide an improved transmission device for a tube bending machine to mitigate the aforementioned problems.